For the first time ever, scientists have detected gravitational waves coming from the collision between two neutron stars.

LIGO/Virgo detections of gravitational waves were paired with a gamma ray burst, which led to the first-ever detection of a binary neutron star collision.

This is the first direct evidence that gamma ray bursts can be caused by colliding neutron stars.

Because it was detected so quickly, optical telescopes were able to point at the location of the collision - and capture images of it across the entire electromagnetic spectrum.

For the first time, we have gravitational wave and electromagnetic wave detections of the same event!

The electromagnetic waves and gravitational waves arrived at Earth at the same time - meaning that for the first time, we have confirmation that gravitational waves travel at the speed of light.

Analysis of the electromagnetic data has confirmed for the first time ever that heavy elements such as gold, platinum and uranium originate in neutron star collisions.

Finally, the combination of the gravitational waves and the redshift of host galaxy NGC 4993 could be combined to measure the age of the universe - and it was remarkably close to our current best estimates.

A lot of questions were answered and mysteries solved, but the event raised new questions too - there's a lot more work for multi-messenger astronomy ahead!

9:30am EDT: It's 0:30am here in Sydney, Australia, so we're basically running on coffee and excitement. But it's always fun to stay awake for these announcements - and this one's going to be so worth it!

The big press conference at the National Press Club in Washington DC is starting in 30 minutes. We'll embed a live stream link down below as it gets closer!

9:31am EDT: While we wait for the announcement in less than half an hour, let's run a refresher course to entertain ourselves and prepare for the big news.

Gravitational waves are a lot like waves in water, or soundwaves in the air, except they're rippling across spacetime. When a massive event happens - like two black holes colliding - it's like dropping a stone into a puddle.

Ripples race out across the universe in all directions at the speed, theoretically at least, of light.

9:35 EDT: In all our excitement we forgot to mention that you should keep refreshing this page to get the latest updates! (Also, sorry in advance for any egregious typos. We made popcorn to celebrate and it's getting in the keyboard.)

9:37 EDT: Gravitational wave astronomy is still extremely fresh! We only got the first ever confirmation that gravitational waves exist last year, in February 2016.

It was one of the biggest astrophysical discoveries in the previous hundred years, and may remain that way for another hundred. It's a huge deal - confirming predictions Einstein made in his theory of general relativity 100 years earlier in 1916.

Meanwhile, a bit more trivia: three of the scientists behind the discovery were just awarded the Nobel Prize in Physics earlier this month. Rainer Weiss of MIT and Barry C. Barish and Kip S. Thorne of CalTech represented over 1,000 scientists who participated in the discovery.

Today, over 1,200 and around 100 institutions around the world participate in the LIGO Scientific Collaboration.

9:43 EDT: Let's talk more about the science! Here's how the gravitational wave detectors work:

LIGO's detectors are known as Michelson interferometers. A laser beam is shone at a mirror down. This splits the beam. Part continues going forward; part splits off to the side. They're bounced off mirrors on the other side, and meet back in the middle, cancelling each other out. This meeting is called interference.

If the arms change length, as they do when a gravitational wave hits, one beam will take longer to travel back to the middle and the two beams won't cancel each other out. The resulting light continues on and is picked up by a photodetector.

9:45am EDT: The music just started on the livestream! We're embedding it at the bottom of this article so we can all watch together.

9:50am EDT: 10 minutes to go! We're loving this jazz.

9:52am EDT: This new gravitational wave astronomy has progressed amazingly fast, by the way.

Until earlier this year, only the two detectors were operational. This meant that scientists could only pinpoint gravitational wave events to a very broad swathe of sky.

But in August a third detector was added - Advanced Virgo. This allows triangulation. Gravitational waves don't hit every detector simultaneously. The order in which detections occur, and the length between them, lets scientists calculate the location with much more accuracy.

10:09am EDT: Astronomers have thought for a long time that heavy elements such as platinum, gold and uranium are created in the collisions between neutron stars.

Now, we have actual concrete evidence of that. So the gold on Earth probably came from neutron star collisions, Reitze says. Even the gold in his grandfather's pocket watch. Awww.

10:10am EDT: David Shoemaker is now telling us about how gravitational waves are measured. The distance the arms move is less than the width of a human hair - that's how sensitive this equipment is.

The length of the inteferometers' arms boosts the signal over distance so that it can be detected. If you're interested in how this works, you should watch this section of the livestream, it's really fascinating.

We've explained it a little above, but Shoemaker is the expert (obviously).

10:15am EDT: "We shared in the joy and excitement of that moment." WE ARE FEELING IT NOW.

The "chirp" signal from the neutron star collision (GW170817) was longer than the chirps from black holes because they're much lighter.

Also, at the same time as the gravitational wave signal came through, a gamma ray burst - caused only by the universe's most violent events - came from the same region of the sky!

That's how the team knew they were onto something different.

10:17am EDT: Jo van den Brand from the Virgo Collaboration has taken the podium. The gravitational wave signal arrived at Virgo in Italy first, then LIGO's two detectors, a few seconds apart.

This is how they figured out where to look for GW170817, in the constellation of Hydra, near galaxy NGC 4993.

10:22am EDT: Julie McEnery works on the Fermi Gamma-Ray Telescope that made the first detections of those gamma ray bursts (along with the ESO's INTEgral gamma-ray burst telescope) that coincided with the gravitational wave detection.

Initially, she said, they didn't think anything of it - until half an hour later, when an email came in, alerting the Fermi team to LIGO-Virgo's detection.

"With these observations, we're not just learning what happens when two neutron stars collide. We're also learning something fundamental about the nature of the universe."

10:27am EDT: Here's why you might hear Albert Einstein mentioned in connection with this new discovery. In 1915 he predicted that the speed of gravitational waves would be the same as the speed of light.

And because the gamma rays and the gravitational rays arrived at the same time, it confirms that gravitational waves do indeed move at the speed of light.

In other words, Einstein nailed it.

10:28am EDT: Marica Branchesi is showing us what happened in the days following the gamma ray detection.

10:32am EDT: LIGO's Vicky Kalogera is here to explain to us the history of these two neutron stars. She says that neutron stars act a bit like lighthouses, with their polar jets pulsing as they rotate.

This has led to them being mistaken for pulsars - the first binary neutron star wasn't discovered until 1974.

These stars are very far apart - over five times the distance between the Earth and the moon - and will not merge for another 300 million years.

10:36am EDT: The two neutron stars in GW170817 lived a very long and happy life, but their orbit inside their galaxy changed when the second star collapsed into a neutron star.

Kalogera describes it as taking a holiday in their twilight years - that's rather poetic and makes us happy.

"We've solved a lot of mysteries, but at the same time, we've opened up a lot of questions. We're hoping that future observations .. are going to answer a lot of those questions."

10:38am EDT: The future of gravitational wave astronomy is looking "golden bright", thank you for that pun.

10:42am EDT: Okay guys, this announcement is wrapping up now and we're in the Q&A phase, so we're just doing a quick recap now to wrap up this live blog as well.

10:50am EDT: If you're keen to keep watching, there will be a second panel at 11:15am starring several supernova experts, diving deeper into the incredible science we're learning from this discovery.

10:58am EDT: And that's all from us tonight! Thanks so much to everyone who tuned in! We'll be buzzing for days and yes, it was absolutely worth staying up so late for this - after all, such historical moments don't come around that often.